Measure free-fall acceleration quickly and easily with this set. The timer starts when the electromagnet releases a steel ball and continues to record as the ball passes through 2 photogates. Determining the period of a pendulum is also quick and easy with the included equipment. The pendulum passes through a single photogate, which captures the time between each pass. Complete apparatus  includes free-fall column with scale and  base stand, spheres, 2 photogates system with digital timer. Supplied with manual.